Support dragging and dropping image files onto the now playing widget and edit tag dialog to set an album's cover art

src/ui/albumcoverchoicecontroller.cpp

@@ -31,11 +31,13 @@
 #include <QAction>
 #include <QCryptographicHash>
 #include <QDialog>
+#include <QDragEnterEvent>
 #include <QFileDialog>
 #include <QImageWriter>
 #include <QLabel>
 #include <QList>
 #include <QMenu>
+#include <QUrl>
 
 const char* AlbumCoverChoiceController::kLoadImageFileFilter =
   QT_TR_NOOP("Images (*.png *.jpg *.jpeg *.bmp *.gif *.xpm *.pbm *.pgm *.ppm *.xbm)");
@@ -44,6 +46,8 @@ const char* AlbumCoverChoiceController::kSaveImageFileFilter =
 const char* AlbumCoverChoiceController::kAllFilesFilter =
   QT_TR_NOOP("All files (*)");
 
+QSet<QString>* AlbumCoverChoiceController::sImageExtensions = NULL;
+
 AlbumCoverChoiceController::AlbumCoverChoiceController(QWidget* parent)
   : QWidget(parent),
 #ifdef HAVE_LIBLASTFM
@@ -228,5 +232,37 @@ QString AlbumCoverChoiceController::SaveCoverInCache(
   image.save(path, "JPG");
 
   return path;
-
+}
+
+bool AlbumCoverChoiceController::IsKnownImageExtension(const QString& suffix) {
+  if (!sImageExtensions) {
+    sImageExtensions = new QSet<QString>();
+    (*sImageExtensions) << "png" << "jpg" << "jpeg" << "bmp" << "gif" << "xpm"
+                        << "pbm" << "pgm" << "ppm" << "xbm";
+  }
+
+  return sImageExtensions->contains(suffix);
+}
+
+bool AlbumCoverChoiceController::CanAcceptDrag(const QDragEnterEvent* e) {
+  foreach (const QUrl& url, e->mimeData()->urls()) {
+    const QString suffix = QFileInfo(url.toLocalFile()).suffix().toLower();
+    if (IsKnownImageExtension(suffix))
+      return true;
+  }
+  return false;
+}
+
+QString AlbumCoverChoiceController::SaveCover(Song* song, const QDropEvent* e) {
+  foreach (const QUrl& url, e->mimeData()->urls()) {
+    const QString filename = url.toLocalFile();
+    const QString suffix = QFileInfo(filename).suffix().toLower();
+
+    if (IsKnownImageExtension(suffix)) {
+      SaveCover(song, filename);
+      return filename;
+    }
+  }
+
+  return QString();
 }

src/ui/albumcoverchoicecontroller.h

@@ -95,10 +95,15 @@ class AlbumCoverChoiceController : public QWidget {
   // Saves the chosen cover as manual cover path of this song in library.
   void SaveCover(Song* song, const QString& cover);
 
+  // Saves the cover that the user picked through a drag and drop operation.
+  QString SaveCover(Song* song, const QDropEvent* e);
+
   // Saves the given image in cache as a cover for 'artist' - 'album'. 
   // The method returns path of the cached image.
   QString SaveCoverInCache(const QString& artist, const QString& album, const QImage& image);
 
+  static bool CanAcceptDrag(const QDragEnterEvent* e);
+
 private:
   QString GetInitialPathForFileDialog(const Song& song,
                                       const QString& filename);
@@ -107,6 +112,9 @@ private:
   static const char* kSaveImageFileFilter;
   static const char* kAllFilesFilter;
 
+  static bool IsKnownImageExtension(const QString& suffix);
+  static QSet<QString>* sImageExtensions;
+
 #ifdef HAVE_LIBLASTFM
   AlbumCoverSearcher* cover_searcher_;
   AlbumCoverFetcher* cover_fetcher_;

src/ui/edittagdialog.cpp

@@ -145,6 +145,7 @@ EditTagDialog::EditTagDialog(QWidget* parent)
   ui_->summary_art_button->setMenu(cover_menu_);
 
   ui_->art->installEventFilter(this);
+  ui_->art->setAcceptDrops(true);
 
   // Add the next/previous buttons
   previous_button_ = new QPushButton(IconLoader::Load("go-previous"), tr("Previous"), this);
@@ -632,8 +633,36 @@ void EditTagDialog::AcceptFinished() {
 }
 
 bool EditTagDialog::eventFilter(QObject* o, QEvent* e) {
-  if (o == ui_->art && e->type() == QEvent::MouseButtonRelease) {
+  if (o == ui_->art) {
+    switch (e->type()) {
+      case QEvent::MouseButtonRelease:
         cover_menu_->popup(static_cast<QMouseEvent*>(e)->globalPos());
+        break;
+
+      case QEvent::DragEnter: {
+        QDragEnterEvent* event = static_cast<QDragEnterEvent*>(e);
+        if (AlbumCoverChoiceController::CanAcceptDrag(event)) {
+          event->acceptProposedAction();
+        }
+        break;
+      }
+
+      case QEvent::Drop: {
+        const QDropEvent* event = static_cast<QDropEvent*>(e);
+        const QModelIndexList sel = ui_->song_list->selectionModel()->selectedIndexes();
+        Song* song = GetFirstSelected();
+
+        const QString cover = album_cover_choice_controller_->SaveCover(song, event);
+        if (!cover.isEmpty()) {
+          UpdateCoverOf(*song, sel, cover);
+        }
+
+        break;
+      }
+
+      default:
+        break;
+    }
   }
   return false;
 }

src/ui/edittagdialog.ui

@@ -30,7 +30,7 @@
      </widget>
      <widget class="QTabWidget" name="tab_widget">
       <property name="currentIndex">
-       <number>1</number>
+       <number>0</number>
       </property>
       <widget class="QWidget" name="summary_tab">
        <attribute name="title">

src/widgets/nowplayingwidget.cpp

@@ -78,6 +78,9 @@ NowPlayingWidget::NowPlayingWidget(QWidget *parent)
   s.beginGroup(kSettingsGroup);
   mode_ = Mode(s.value("mode", SmallSongDetails).toInt());
 
+  // Accept drops for setting album art
+  setAcceptDrops(true);
+
   // Context menu
   QActionGroup* mode_group = new QActionGroup(this);
   QSignalMapper* mode_mapper = new QSignalMapper(this);
@@ -370,16 +373,14 @@ void NowPlayingWidget::resizeEvent(QResizeEvent* e) {
 void NowPlayingWidget::contextMenuEvent(QContextMenuEvent* e) {
   // initial 'enabled' values depending on the kitty mode
   album_cover_choice_controller_->cover_from_file_action()->setEnabled(!aww_);
-  album_cover_choice_controller_->cover_to_file_action()->setEnabled(!aww_);
+  album_cover_choice_controller_->cover_to_file_action()->setEnabled(aww_);
   album_cover_choice_controller_->cover_from_url_action()->setEnabled(!aww_);
   album_cover_choice_controller_->search_for_cover_action()->setEnabled(!aww_);
   album_cover_choice_controller_->unset_cover_action()->setEnabled(!aww_);
   album_cover_choice_controller_->show_cover_action()->setEnabled(!aww_);
 
   // some special cases
-  if(aww_) {
+  if (!aww_) {
-    album_cover_choice_controller_->cover_to_file_action()->setEnabled(true);
-  } else {
   #ifndef HAVE_LIBLASTFM
     album_cover_choice_controller_->cover_from_file_action()->setEnabled(false);
     album_cover_choice_controller_->search_for_cover_action()->setEnabled(false);
@@ -476,3 +477,18 @@ void NowPlayingWidget::Bask() {
   big_hypnotoad_.reset(new FullscreenHypnotoad);
   big_hypnotoad_->showFullScreen();
 }
+
+void NowPlayingWidget::dragEnterEvent(QDragEnterEvent* e) {
+  if (AlbumCoverChoiceController::CanAcceptDrag(e)) {
+    e->acceptProposedAction();
+  }
+
+  QWidget::dragEnterEvent(e);
+}
+
+void NowPlayingWidget::dropEvent(QDropEvent* e) {
+  album_cover_choice_controller_->SaveCover(&metadata_, e);
+  NowPlaying(metadata_);
+
+  QWidget::dropEvent(e);
+}

src/widgets/nowplayingwidget.h

@@ -79,6 +79,8 @@ protected:
   void paintEvent(QPaintEvent* e);
   void resizeEvent(QResizeEvent*);
   void contextMenuEvent(QContextMenuEvent* e);
+  void dragEnterEvent(QDragEnterEvent* e);
+  void dropEvent(QDropEvent* e);
 
 private slots:
   void SetMode(int mode);